1. Field of the Invention
The present invention relates to a lighting system configured to reduce the standby power.
A variation of the present invention relates to an LED lighting apparatus that uses LEDs (light emitting diodes) as the light source.
A variation of the present invention relates to an LED lighting apparatus which uses LEDs (light emitting diodes) as the light source and which is configured to be operable by remote control.
A variation of the present invention relates to an LED lighting apparatus including LED chips.
2. Description of the Related Art
Reduction of use of electric power and power-saving have long been demanded and are in increasing demand in recent years. In response to such a demand, LED lighting using LEDs (light emitting diodes) is increasingly used mainly at home. LED lighting is superior to lighting using an incandescent lamp, fluorescent lamp etc. in terms of lower power consumption, lower heat generation, longer life, higher reliability and higher response speed.
Patent Document 1 (JP-A-H11-233283) discloses a lighting system, in which an AC power source is connected to a lamp via a rectifier, a chopper, and an inverter. The chopper is provided with a starting circuit connected from the rectifier or another rectifier connected to the AC power source. In this arrangement, when DC power is not supplied to the chopper controller, the starting circuit is not operational, so that the standby power reduces.
Patent Document 2 (JP-A-H11-312591) discloses a lighting system including a light source, a lighting device for driving the light source, a microcomputer for controlling the state of the light source by controlling the lighting device, a receiving part for sending a signal to the microcomputer on receiving a remote control signal, and a signal detecting part for detecting the signal from the receiving part. When the light source is in the OFF state, the microcomputer is supplied with no DC power and is in a stand-by state, while the receiving part and the signal detecting part are intermittently supplied with DC power and are in a stand-by state. When the receiving part outputs a signal upon receiving a remote control signal, DC power is supplied to the microcomputer in response to the signal outputted from the signal detecting part, and DC power is continuously supplied to the receiving part and the signal detecting part.
Patent Document 3 (JP-A-2009-4206) discloses a lighting device, a lighting apparatus and a lighting system. A microcomputer for controlling the lighting of a discharge lamp is supplied with voltage only during its operation and when the first switching element is kept on after its operation, and is not supplied with voltage in other conditions including a stand-by state. With this arrangement, the stand-by power of the lighting device can be kept nearly 0.
Patent Document 4 (JP-A-2007-265818) discloses lighting apparatus which uses in combination two types of LEDs having a low color temperature and a high color temperature. With this lighting apparatus, light emission of five colors, i.e., an incandescent color, a warm white color, a white color, a daylight white color and a daylight color can be achieved by changing the brightness of at least one of the two types of LEDs.
Patent Document 5 (JP-A-2007-122950) discloses a lighting system having high color rendering properties. The lighting system includes two or more lamps selected from a group consisting of lamps having LEDs only and lamps including LEDs and a fluorescent substance to be excited by the light from the LEDs. The lighting system further includes a controller for controlling light output from these lamps.
FIG. 12 is a circuit diagram of a conventional lighting system applicable to e.g. a ceiling light. A ceiling light is a lighting apparatus to be fixed directly to the ceiling of a room to illuminate the entire room. To illuminate the entire room by using a single lighting system, the lighting system needs to have a size and brightness sufficient for the size of the room.
The lighting system 1200 includes a main power source 11, a control circuit 12, a daylight white color light source driver 21, an incandescent color light source driver 22, a first light source unit 31 and a second light source unit 32. The control circuit 12 includes an AC/DC converter 13, a transformer 14, a DC/DC converter 15, a signal processing circuit 16, and a remote controller receiver 17.
The main power source 11 is e.g. a commercial power source, and its AC voltage AC1 is e.g. 100V. The AC/DC converter 13, the transformer 14, the DC/DC converter 15 are provided for generating a DC voltage for driving the signal processing circuit 16. The signal processing circuit 16 is connected to a remote controller receiver 17. The remote controller receiver 17 responds to a signal transmitted from a remote controller transmitter, not shown. The lighting part of the ceiling light, i.e., the first light source unit 31 and the second light source unit 32 are turned on or off in accordance with the signal transmitted to the remote controller receiver 17.
The signal processing circuit 16 supplies a Pulse Width Modulation (PWM) signal to the daylight white color light source driver 21 and the incandescent color light source driver 22.
The daylight white color light source driver 21 and the incandescent color light source driver 22 drive the first light source unit 31 having a color temperature of 5000 K (Kelvin) and the second light source unit 32 having a color temperature of 2900 K (Kelvin), respectively. Each of the first light source unit 31 and the second light source unit 32 includes e.g. a LED or a plurality of LEDs connected in series.
In the conventional lighting system 1200 shown in FIG. 12, the daylight white color light source driver 21 and the incandescent color light source driver 22 are held in a stand-by state even when the first light source unit 31 and the second light source unit 32, i.e., the ceiling light is in the OFF state. For instance, when the standby power at the control circuit 12 is 0.5 W and the standby power of each of the daylight white color light source driver 21 and the incandescent color light source driver 22 is 0.5 W, the entire lighting system 1200 requires a standby power of 1.5 W.
For easier understanding, the lighting system 1200 shown in FIG. 12 is described as including two light source drivers, i.e., the daylight white color light source driver 21 and the incandescent color light source driver 22. However, a larger number of light source drivers may be employed, and the standby power increases with the number of the light source drivers.
Conventionally, a lighting system including a light source such as an incandescent lamp, a fluorescent lamp or the like has been used as a lighting system for illuminating a room in a house and so on. In recent years, however, in accordance with the enhancement in brightness of light emitting diodes (hereinafter referred to as LEDs), various lighting systems have been proposed which use LEDs having a smaller size, a lower power consumption and a longer life, instead of conventional light sources.
For instance, an LED lamp including an LED chip has been proposed as a replacement for an incandescent lamp. Further, an LED lighting system is also proposed which has the function of adjusting the brightness and chromaticity of the light. For instance, some LED lighting systems incorporate a plurality of types of LED lamps that emit light of different color temperatures, so that light of a desired color is obtained by adjusting the brightness of each type of the LED lamps. Such LED lighting systems are used as a downlight or a ceiling light, for example.
Among such LED lighting systems, there exists an LED lighting system, as disclosed in e.g. Patent Document 6 (JP-A-2008-300124), which is configured to generate composite light of white LEDs and red LEDs while setting the chromaticity of light from the white LEDs to a certain range, in order to obtain a composite light having a desired color temperature and high color rendering properties.
However, since such a conventional LED lighting system uses white LEDs of different color temperatures, variations of LEDs are produced in the manufacturing process, resulting in variations in brightness. Such variations in brightness of the LEDs lead to non-uniform brightness. Further, when LEDs of different color temperatures are employed, such variations in brightness leads to variations in color of composite light. Thus, before mounting the LEDs, the LEDs are classified into e.g. nine groups based on the combination of brightness and color, and LEDs of a certain group having variations in a limited range are mounted.
However, in the above-described method, measurement needs to be performed with respect to each of the LEDs for classification into groups, which needs much time and cost. Further, even when variation is suppressed to a certain degree by the classification, the brightness or chromaticity of the LEDs may not correspond to the brightness or chromaticity satisfactory to the user.
An LED lighting apparatus including an LED chip has been developed as a replacement for a lighting apparatus of a type for attaching e.g. a fluorescent lamp. Some of lighting apparatuses to be fixed to a ceiling are configured such that operations such as turning on or off the light and adjustment of the light can be performed by remote control (See Patent Document 7 (JP-A-2008-108598), for example).
FIG. 26 schematically illustrates an example of LED lighting apparatus designed to be fixed to a ceiling to illuminate a room. The LED lighting apparatus 90 shown in FIG. 26 includes a main body 91 to be fixed to a ceiling, and a remote controller 92 for operating the main body 91. The main body 91 includes a plurality of LED chips and a control unit for controlling the lighting of the LED chips in accordance with a signal from the remote controller 92. The LED lighting apparatus 90 is designed to allow adjustment of the brightness of the main body 91 and adjustment of the color of the light emitted from the main body 91. Accordingly, the remote controller 92 includes a button 92a for brightness adjustment and a button for color adjustment, in addition to a button for turning on or off the light.
For instance, the LED lighting apparatus 90 can be designed such that the brightness of the main body 91 increases by a predetermined one step when the brightness adjustment button 92a is pressed shorter than 1.25 sec. and that the brightness of the main body 91 increases continuously when the brightness adjustment button 92a is pressed longer than 1.25 sec. With this arrangement, the operation to increase the brightness step by step and the operation to increase the brightness continuously can be performed by using the same button 92a, which allows the remote controller 92 to be made simple.
However, the sense of time is different from person to person, so that even when the user, who intended to continuously change the brightness, thinks that they have pressed the brightness adjustment button 92a for a sufficiently long time, the actual pressing time of the brightness adjustment button 92a may be shorter than 1.25 sec. In such a case, brightness changes by one step, centrally to the user's intension. Such a situation where the user cannot operate the lighting apparatus as desired may cause the user to feel stress.
An LED lighting apparatus including an LED chip has been developed as a replacement for a lighting apparatus of a type for attaching e.g. a fluorescent lamp. A lighting apparatus to be fixed to a ceiling is generally called a ceiling light. For instance, Patent Document 8 (JP-A-2008-300203) discloses a conventional LED lighting apparatus used as a ceiling light.
FIG. 47 shows an example of ceiling light. The LED lighting apparatus 900 shown in the figure is in the form of a thin disc as a whole and used as fixed to a ceiling. The LED lighting apparatus 900 includes a plurality of LED chips 910D, a plurality of substrates 920D, and a cover 930 covering the LED chips 910D. As shown in FIG. 47, each substrate 920D is curved along the circumferential direction. Each substrate 920D is prepared by cutting a rectangular substrate material. As compared with cutting rectangular substrates out of a rectangular substrate material, cutting substrates having a curved shape out of a rectangular substrate provides a smaller number of substrates. Moreover, when any failure occurs, the substrate 920D needs to be disposed of, which leads to waste and an increase in the manufacturing cost.
Moreover, when rectangular substrates are simply arranged in a circular region, the LED chip 910D cannot be arranged uniformly, so that part of the LED lighting apparatus 900 may become dark.
An LED lighting apparatus including an LED chip has been developed as a replacement for a lighting apparatus of a type for attaching e.g. a fluorescent lamp. A lighting apparatus to be fixed to a ceiling is generally called a ceiling light.
FIG. 65 shows an example of conventional LED lighting apparatus for use as a ceiling light (see Patent Document 8, for example). The LED lighting apparatus 900 shown in the figure has a thin circular shape as a whole and is used as attached to a ceiling 800. The LED lighting apparatus 900 includes a plurality of light source units 910, a reflective surface 920 and a cover 930. The light source units 910 incorporate LED chips (not shown) and are arranged on a circle. The reflective surface 920 is a surface of a metal plate that is painted white, for example. As shown in the figure, the reflective surface 920 is arranged on the radially inner side of the light source units 910 arranged on a circle. Light from the light source units 910 is reflected by the reflective surface 920 to travel downward in the figure. The cover 930 is made of e.g. a resin material that transmits light while diffusing, and hence, transmits the light, reflected by the reflective surface 920, downward in the figure while diffusing.
The LED lighting apparatus 900 is designed such that light is emitted through the cover 930 covering the light source units 910 and the reflective surface 920. Thus, the LED lighting apparatus 900 as a whole has a relatively large thickness. To enhance the appearance of a living room or the like to which the LED lighting apparatus 900 is installed, further thickness reduction of the LED lighting apparatus 900 is demanded. In addition to the LED lighting apparatus 900 used as a ceiling light to be fixed to a ceiling 800, an LED lighting apparatus of a type called a pendant light is also demanded which emits light toward the floor from a position spaced a certain distance from the ceiling.
An LED lighting apparatus including an LED chip has been developed as a replacement for a lighting apparatus of a type for attaching e.g. a fluorescent lamp. A lighting apparatus to be fixed to a ceiling is generally called a ceiling light.
FIG. 77 shows an example of conventional LED lighting apparatus for use as a ceiling light (see Patent Document 8, for example). The LED lighting apparatus 900 shown in the figure is used as attached to a ceiling 800. The LED lighting apparatus 900 includes a plurality of light source units 910, a reflective surface 920 and a cover 930. The light source units 910 incorporate LED chips (not shown). The reflective surface 920 is a surface of a metal plate that is painted white, for example. Light from the light source units 910 is reflected by the reflective surface 920 to travel downward in the figure. The cover 930 is made of e.g. a resin material that transmits light while diffusing, and hence, transmits the light, reflected by the reflective surface 920, downward in the figure while diffusing. The LED lighting apparatus 900 is designed to achieve both the good appearance along a ceiling and the uniform illumination of a room.
However, reduction in thickness of the LED lighting apparatus 900 accompanies increased limitation on the shape of the reflective surface 920. Such limitation hinders uniform illumination by the LED lighting apparatus 900.
An LED lighting apparatus including an LED chip has been developed as a replacement for a lighting apparatus of a type for attaching e.g. a fluorescent lamp. A lighting apparatus to be fixed to a ceiling is generally called a ceiling light. For instance, Patent Document 8 discloses an LED lighting apparatus for use as a ceiling light.
FIG. 88 shows an example of ceiling light. The LED lighting apparatus 900 shown in the figure has a thin circular shape as a whole and used as fixed to a ceiling. The LED lighting apparatus 900 includes a plurality of LED substrates 910G, a plurality of LED chips 920G mounted on each of the LED substrates 910G, and a cover 930 covering the LED substrates 910G. The plurality of LED substrates 910G are arranged such that the edges of each LED substrate face edges of adjacent LED substrates, thereby forming a ring-like shape. A pair of connectors 940, 950 are provided at facing edges of adjacent LED substrates 910G.
To each of the connectors 940, 950 is connected a connection end of a wiring 960, which is made of a single core wire. The connectors 940, 950 of each pair are arranged such that the connection portions face each other. Thus, both the connection direction (first connection direction) of a connection end to the connector 940 and the connection direction (second connection direction) of a connection end to the connector 950 are along the circumferential direction n1 of the LED substrates 910G. To achieve proper connection to each connector 940, 950, the wiring 960 is made to have a certain margin and curved along the LED substrate 910G, as shown in FIG. 88.
However, according to the above-described structure in which the connectors 940 and 950 face each other, the wiring 960 rotates easily when rotation moment is exerted between the connectors 940, 950 and the wiring 960. Thus, in using the LED lighting apparatus 900, the curved portion of the wiring 960 may move and hinder the progress of the light from the LED chips 920G, making part of the LED lighting apparatus 900 dark.    Patent Document 1: JP-A-H11-233283    Patent Document 2: JP-A-H11-312591    Patent Document 3: JP-A-2009-4206    Patent Document 4: JP-A-2007-265818    Patent Document 5: JP-A-2007-122950    Patent Document 6: JP-A-2008-300124    Patent Document 7: JP-A-2008-108598    Patent Document 8: JP-A-2008-300203